▎ 摘　　要

The properties of the dielectric constant of water in confined systems vary greatly, which has a significant impact on its applications in electrochemistry, membrane treatment and energy storage. For example, in graphene pores, the physical properties are affected by factors such as membrane pore size and degree of oxidation, but few studies have been conducted in this regard. Therefore, in order to further understand the influence of pore size and oxidation degree on the dielectric properties, molecular dynamics simulation method was used to explore the dielectric behavior of water in the double-layer graphene nanochannels with different pore size and oxidation degree. At the same time,as a local diagonal tensor in a constrained system, the dielectric constant can be defined in two directions parallel to and orthogonal to the wall. The experimental results show that water molecules exhibit a greater spatial and orientation order in a narrow environment, and the dielectric constant of confined water decreases with the decrease of the space of the nanochannels. With the increase of oxidation degree, the influence of the wider spacing on the dielectric constant is greater than that of the narrower nanochannel. For the widest channels (d=1.2 nm), the dielectric constant of the graphene bilayer decreased with the increase of oxidation degree, while for the relatively narrow chan. nels (d=0.6 nm,0.9 nm), the dielectric behavior showed a non-monotonic trend. To understand the physics behind this, we calculated the number of hydrogen bonds in the three nanochannels. The results showed that the number of hydrogen bonds and the dynamic stability (corresponding to the fastest decay rate) were the lowest at 1.2 nm, indica. ting that the water molecules were more unstable and disordered in the large nanoscale than in the 0.6 nm and 0.9 nm nanoscale. This work emphasizes the significant importance of regulating the interlamellar distance for understanding the permeance of water and its transport mechanism and provides fundamental theories for the preparation of ad. vanced materials based on graphene oxide (GO)and their application in water treatment.